1. Field
Aspects described herein relate generally to a low-voltage, multi-beam, multi-megawatt (MW) Radio Frequency (RF) source for accelerators.
2. Background
Aspects described herein relate generally to a low-voltage, multi-beam RF source/amplifier for accelerators, e.g. a low-voltage Multi-Beam Klystron (MBK).
RF sources can be used to power accelerators, such as ILC-type SRF accelerator structures at an acceleration gradient up to 35 MeV/m. This type of acceleration structure is planned for use in the ILC main linear accelerators (linacs), which is described in more detail in “ILC Reference Design Report, August 2007, ILC Global Design Effort and World Wide Study,” a copy of which can be found at the Linear Collider Collaboration Website, and the entire contents of which are incorporated herein by reference.
Such RF source have other potential applications, such as in the high-energy portion of the proton linac for Project-X that is under development at Fermi National Accelerator Laboratory (FNAL), which is described in more detail in G. Appolinary, “ProjectX Linac, a copy of which can be found at the Project X. website, and the entire contents of which are incorporated herein by reference.
In ILC as well as in Project-X, the main lilacs would be constructed from one-meter long, nine-cell superconducting cavities operating at 1.3 GHz, Groups of 8-to-9 such cavities would be installed in a common cryostat, e.g. as described in S. Nagaitsev, “High Energy Linac Overview,” Nov. 12, 2007, a copy of which can be found at the Project X website, and, the entire contents of which are incorporated herein by reference.
The accelerating gradients are to be about 25 MeVim (Project-X) and 31.5 MeV/m (ILC), The RF-power would be generated by klystrons, each feeding nine-cell cavities. The required peak power per klystron is 10 MW, including a 10% overhead for correcting phase errors during the beam pulse which arise from Lorentz force detuning and microphonics The RF pulse length is 1.5 ms, which includes the beam pulse length of ˜1000 μs, and the cavity fill time of about 500 μs. The repetition rate is 5-10 Hz. Multiple versions of 10 MW MBK's have so far been designed and built as RF sources. Each includes an efficiency of around 60-65%. However, each of these tubes require a beam voltage of 117 kV, and thus one must employ a pulse modulator, pulse transformer, oil tank, high-voltage cables, and all the exceptional safety and maintenance provisions that accompany a high-voltage installation. Such high-voltage MBKs are described in A. Beunas, G. Faillon and S. Choroba, “A High Power Long Pulse High Efficiency Multi-Beam Klystron,” a copy of which can be found at the Fermilab website, A. Balkoum, H. P. Bohlen, M. Cattelino, L. Cox, M. Cusick, S. Forrest, F. Friedlander, A. Staprans, E. L. Wright, L. Zitelli, K. Eppley, “Design and Operation of a High Power L-Band Multiple Beam Klystron, “Proceedings of a 2005 Particle Accelerator Conference, Knoxville, 2005, p. 2170, and Y. H. Chin, S. Choroba, M. Y. Miyake, Y. Yano, “Development of Toshiba L-Band Multi-Beam Klystron for European XFEL Project,” Proceedings of 2005 Particle Accelerator Conference, Knoxville, 2005, p. 3163, the entire contents of each of which are incorporated herein by reference.
Thus, there is a need in the art for an RF amplifier with similar output parameters, but operating with a lower beam voltage.